According to a peer-reviewed study published in Pediatric Research on Tuesday, breastfeeding women infected with COVID-19 could not transmit the virus through breast milk. The study validated a small number of peer-reviewed studies and supporting recommendations from health organizations advising mothers to continue breastfeeding after infection and vaccination.

The lead author, Dr. Paul Krogstad, suggested that breastfeeding is not likely to be a hazard. The study was the largest of its kind so far and provided "substantial" support for several smaller studies with similar findings. The researchers stated that the study will assist in bolstering guidance from health organizations like the Centers for Disease Control and Prevention and the World Health Organization. There are many benefits to breastfeeding, but there are rare cases where breast milk can transmit diseases, such as HIV, human T-cell lymphotropic virus, and Ebola virus.

However, in 2020, the WHO advised that women with COVID-19 can breastfeed, but warned that they should take precautions to prevent passing on the infection by other means, including wearing a mask during feeding, washing their hands before and after touching the baby, and routinely cleaning surfaces they’ve touched. On the other hand, vaccination coverage among pregnant and breastfeeding women is well below average, fuelled by muddled public health opinion suggesting the shots can somehow harm a mother, child, or both. Though some vaccines can transmit the infection to breastfed infants, the CDC data has cited smallpox and yellow fever vaccines as examples, not the Covid-19 vaccines. Also, antibodies from the mother are passed on in breast milk, providing some degree of protection against the virus. 

(Source: https://www.forbes.com/sites/roberthart/2022/01/18/breast-milk-contains-covid-genetic-material-but-infected-mothers-wont-transmit-virus-through-breastfeeding-study-finds/?sh=413539395395 )